In the wireless communication infrastructure industry, one technique that is utilized to enhance radio power amplifier (PA) efficiency is envelope tracking (ET). Envelope Tracking is a known approach to RF power amplifier design in which the power supply voltage applied to the PA is constantly adjusted to ensure that the PA is operating at peak efficiency over output power range.
Generally speaking, envelope tracking is high-efficiency architecture for power amplifiers. However, it is typically not used in commercial base transceiver station (BTS) power amplifiers because the necessary envelope modulator is difficult to implement.